{"id":"CVE-2026-109783","title":"Mitigation bypass in the File Handling component","summary":"Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox ESR 153.5 and Thunderbird 153.5.","severity":"high","published":"2026-10-13","updated":"2026-10-13","sourceUpdated":"2026-10-13T19:18:42.873","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-109783","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2075533","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-108/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-110/","label":"security@mozilla.org"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-10-13T13:27:04.019Z","vendor":"Mozilla","product":"Firefox","affected":["Firefox","Thunderbird"],"epss":0.00273,"epssPercentile":0.19565,"cvss":8.3,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-26T19:24:56.139735Z"},"cvssSource":"adp","slug":"CVE-2026-109783","body":"## Overview\n\nMitigation bypass in the File Handling component. This vulnerability was fixed in Firefox ESR 153.5 and Thunderbird 153.5.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":46,"depthScoreParts":{"impact":45.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":229776,"id":"CVE-2026-109783","ts":1793047365695,"field":"cvss","old":null,"new":"8.3"},{"seq":229775,"id":"CVE-2026-109783","ts":1793047365695,"field":"severity","old":"none","new":"high"}]}